There has been known a wireless power transfer system that wirelessly transmits power from a power transmission coil of a power transmitter to a power reception coil of a power receiver and supplies the power to a load of a power receiver side. In the wireless power transfer system, relative positions of the power transmission coil and the power reception coil are misaligned, so that the power supplied to the power reception coil and the load changes.
For example, Patent Literature 1 discloses a method of adjusting a voltage generated in the power reception coil by performing frequency control of power supplied to the power transmission coil in the power transmitter, when the misalignment occurs.